1. Field of the Invention
The present invention relates to a method for the production of new compounds with adjusted isocyanurate group content, as well as the compounds obtainable by this method.
2. Description of the Prior Art
The production of masked isocyanates, also called isocyanate yielders, is known and is described in Houben-Weyl, Methoden des organischen Chemie XIV/2 pp. 61-70. Blocking agents known are tertiary alcohols, phenols, acetoacetic ester, malonic ester, acetylacetone, phthalimide, imidazole, hydrogen chloride, hydrogen cyanide and .epsilon.-caprolactam.
These masked isocyanates possess the property of reacting like isocyanates at elevated temperature. The splitting occurs easier the more acid the H-atom of the masking group is. Such blocked isocyanates are described in DT-OS No. 21 66 432. Also, terminally blocked isocyanates, which contain in addition uretdione groups, have been described in DT-OS No. 25 02 934.
Surprisingly there are no references in the literature to aliphatic polyisocyanates exhibiting isocyanurate groups and terminally blocked isocyanate groups. To be sure, blocked aromatic isocyanurates for producing heat-resistant adherent urethane bake-on lacquers, especially for electric wire insulation in a JA-A5 No. 73,30453, filed 12/24/69, have been proposed. The production of aliphatic polyisocyanates containing such blocked isocyanurate groups is, however, still unknown.